Tune up question

[tookentigerlily]

I just wanted to run this question by the pros. I have an OMC 3.0 Cobra that is trying to push a 16.5' 1990 Sunbird 175, just got a shift problem fixed and am now moving on to the engine.

It does not get up to speed at all, the enigine is maxing out at 3 grand on the tach and once it gets to that point it starts sputtering. I have only been able to get to 20 mph max. I would think that it should go faster than that. I am going to be doing a complete tune up, fuel filter change, and also checking the carb and compression. Since I am new to boating I wanted to make sure that I am not forgetting anything when it comes to doing a tune up on a boat engine. Any help would be greatly appreciated. Thanks.

Bill

 

[Don S]

Re: Tune up question

List of possible causes of low WOT (Wide Open Throttle) rpm.

Engine Won't Reach Operating RPM. Check

• Fuel condition. Type and Octane possibly old fuel
• Propeller pitch or diameter, damaged blades
• Restricted fuel pickup tube or anti siphon valve Fuel System Test
• Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
• Marine growth on hull and outdrive
• Wrong gear ratio in outdrive
• Restricted carburetor air intake (clogged flame arrestor)
• Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
• Poor cylinder compression Compression Test
• Carburetor defective, or wrong type.
• Fuel pump pressure and vacuum
• Boat overloaded, improperly loaded, or improperly trimmed.
• Engine Overheating
• Engine timing and ignition system operation
• Remote control cables and linkage for proper travel to open throttle plates fully.